The need for increasing the production of energy from renewable energy sources is critical these days but the penetration of the relevant systems is not satisfactory for several reasons. The greatest problem relates to the storage of the produced energy and its subsequent use for the production of useful energy, mainly electricity. Renewable energy sources are productive when there are suitable conditions and production becomes heavily dependent on them. E.g., wind generators can produce wind energy only when there is wind. With no wind, or stronger/ weaker wind than the specified, there is no energy production. The same happens with energy from the sun. In effect, it is almost impossible to match consumers’ demands with the energy provided from the renewable sources and energy should be stored. However, the proposed solutions to storing and afterward use of the energy from renewable sources are very expensive and ineffective, leading producers to distribute energy directly to the grid instead of storing it. This has a negative impact on the grid, which is burdened by the variation of the energy produced and the level of energy that it can absorb.
A Greek engineering SME provides a total answer to the problems of energy storage and production from renewable energy sources. The Greek company has patented a system using compressed air. The system is completely independent from periodic weather variations and can be ideally connected to the grid, providing maximum energy immediately and when needed. The system uses the energy from wind generators, or photovoltaic panels, or their combination, in order to compress air in high pressure. The compressed air is then stored in metal tanks, in high pressure. When needed, the compressed air drives a normal cryogenic turbo-expander for the production of energy through a generator, exactly at the required amount and time, almost immediately (few seconds needed), to the grid.
The energy utilization efficiency of the offered system reaches 80-83%, as theoretically calculated by a German faculty of engineering and as experienced in the prototype system’s operation. The performance of the turbines can reach 90%, as tested by the large manufacturer which procures them.
The storage takes place in metal-made air tanks. These have the shape of a tube and are qualified to hold 300 bars of pressure, much higher than the desired 200-250 bars needed by the system. For higher power-demand applications, more connected tanks are used. The stored energy in such a tank provides power for days or weeks without significant losses.
The Greek company has completed a pilot project for the production of 12KW of electric energy. The stored energy is reaching 50 KWh. The project is available for demonstration of the system’s advantages and feasibility.
The Greek company is looking for industrial companies active in the field of energy production or renewable energy sources. The partner is sought for co-exploitation, certification and scale-up of the system so as it reaches the market. Joint venture agreement is sought.